第２回 Hadoop 輪読会

1. Hadoop 3 Hadoop

2. Hadoop • - - - • HDFS(Hadoop Distributed Filesystem)

3. HDFS • - ‣ MB, GB, TB - ‣ - ‣ ‣

4. HDFS • - ‣ - ‣ - ‣ ‣

5. HDFS • - 64MB - ‣ ‣ ‣

6. HDFS • - / - ( ) - ( )

7. HDFS • - ( ) - ( )

8. HDFS • - - -

9. HDFS • - ( , ) -

10. HDFS • - NameNode SecondaryNameNode

11. HDFS • - open() append() write() NameNode SecondaryNameNode

18. • hadoop fs -copyFromLocal <localsrc> ... <dst> • hadoop fs -copyToLocal <src> <localdst> • hadoop fs -ls <path> • hadoop fs -mkdir <path> • hadoop fs -help

19. Hadoop •hadoop fs -ls ﬁle:/// •hadoop fs -ls hdfs:/// •hadoop fs -ls hftp:/// URI java local ﬁle org.apache.hadoop.fs.localFileSystem HDFS hdfs org.apache.hadoop.hdfs.DistributesFileSystem HFTP hftp org.apache.hadoop.hdfs.HftpFileSystem HSFTP hsftp org.apache.hadoop.hdfs.HsftpFileSystem HAR har org.apache.hadoop.fs.HarFileSystem KFS kfs org.apache.hadoop.fs.kfs.KosmosFileSystem FTP ftp org.apache.hadoop.fs.ftp.FTPFileSystem S3 s3n org.apache.hadoop.fs.s3native.NativeS3FileSystem ( ) S3 s3 org.apache.hadoop.fs.S3FileSystem ( )

20. • Thrift • C - libhdfs • FUSE(FileSystem in Userspace) • WebDAV • - HTTP, FTP( )

21. Java • Hadoop URL public class URLCat { static { URL.setURLStreamHandlerFactory(new FsUrlStreamHandlerFactory()); } public static void main(String[] args) throws Exception { InputStream in = null; try { in = new URL(args[0]).openStream(); IOUtils.copyBytes(in, System.out, 4096, false); } finally { IOUtils.closeStream(in); } } }

22. Java • FileSystem API public class FileSystemCat { public static void main(String[] args) throws Exception { String uri = args[0]; Configuration conf = new Configuration(); FileSystem fs = FileSystem.get(URI.create(uri), conf); InputStream in = null; try { in = fs.open(new Path(uri)); IOUtils.copyBytes(in, System.out, 4096, false); } finally { IOUtils.closeStream(in); } }

23. Java • FSDataInputStream public class FSDataInputStream extends DataInputStream implements Seekable, PositionedReadable { // } public interface Seekable { void seek(long pos) throws IOException; long getPos() throws IOException; boolean seekToNewSource(long targetPos) throws IOException; }

24. Java • FSDataInputStream public class FileSystemDoubleCat { public static void main(String[] args) throws Exception { String uri = args[0]; FileSystem fs = FileSystem.get(URI.create(uri), new Configuration()); FSDataInputStream in = null; try { in = fs.open(new Path(uri)); IOUtils.copyBytes(in, System.out, 4096, false); in.seek(0); IOUtils.copyBytes(in, System.out, 4096, false); } finally { IOUtils.closeStream(in); } } }

25. Java • FSDataInputStream public class FSDataInputStream extends DataInputStream implements Seekable, PositionedReadable { // } public interface PositionedReadable { int read(long position, byte buffer[], int offset, int length) throws IOException; void readFully(long position, byte buffer[], int offset, int length) throws IOException; void readFully(long position, byte buffer[]) throws IOException; }

26. Java • - public FSDataOutputStream create(Path f) throws IOException - public FSDataOutputStream append(Path f) throws IOException

27. Java • FSDateOutputStream - FileSystem create(), append() - public class FSDataOutputStream extends DataOutputStream implements Syncable { public long getPos() throws IOException { // } // }

28. Java • - public boolean mkdirs(Path f) throws IOException

29. Java • FileStatus status = fs.getFileStatus(new Path("hdfs://localhost/hogehoge")); status.isDir(); // status.getLen(); // status.getModificationTime(); // status.getReplication(); // status.getBlockSize(); // ( 64MB) status.getOwner(); // status.getGroup(); // status.getPermission().toString(); //

30. Java • - public FileStatus[] listStatus(Path f) throws IOException; - public FileStatus[] listStatus(Path f, PathFilter filter) throws IOException; - public FileStatus[] listStatus(Path[] files) throws IOException; - public FileStatus[] listStatus(Path[] files, PathFilter filter) throws IOException;

31. Java • public class ListStatus { public static void main(String[] args) throws Exception { String uri = args[0]; Configuration conf = new Configuration(); FileSystem fs = FileSystem.get(URI.create(uri), conf); Path[] paths = new Path[args.length]; for (int i = 0; i < paths.length; i++) { paths[i] = new Path(args[i]); } FileStatus[] status = fs.listStatus(paths); for (FileStatus stat : status) { System.out.println(stat.getPath().toUri().getPath()); } } }

32. Java • - public FileStatus[] globStatus(Path pathPattern) throws IOException - public FileStatus[] globStatus(Path pathPattern, PathFilter filter) throws IOException

33. Java • [ab] {a,b} [^ab] {a,b} {a,b} (a b ) [a-b] a b {a,b} (a b ) a b [^a-b] {a,b} a b ¥c c c

34. Java • public interface PathFilter { boolean accept(Path path); }

35. Java • public class RegexExcludePathFilter implements PathFilter { private final String regex; public RegexExcludePathFilter(String regex) { this.regex = regex; } @Override public boolean accept(Path path) { return !path.toString().matches(regex); } } fs.globStatus(new Path("/2007/*/*"), new RegexExcludePathFilter("^.*/2007/12/31$"));

36. Java • - public boolean delete(Path f, boolean recursive) throws IOException;

37. • HDFS DistributedFileSystem NameNode FSDataInputStream DateNode1 DateNode2 DateNode3 DateNode4 block1 block3 block1 block2 block4 block4 block2 block3

38. • open(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode FSDataInputStream DateNode1 DateNode2 DateNode3 DateNode4 block1 block3 block1 block2 block4 block4 block2 block3

39. • “/aaa.txt” open(new Path(“/aaa.txt”)) ( ) HDFS DistributedFileSystem NameNode FSDataInputStream DateNode1 DateNode2 DateNode3 DateNode4 block1 block3 block1 block2 block4 block4 block2 block3

40. • “/aaa.txt” open(new Path(“/aaa.txt”)) ( ) HDFS DistributedFileSystem NameNode aaa.txt : block1, block2. block3, block4 block1 : DataNode1, DataNode3 block2 : DataNode3, DataNode4 FSDataInputStream block3 : DataNode2, DataNode3 block4 : DataNode1, DataNode2 DateNode1 DateNode2 DateNode3 DateNode4 block1 block3 block1 block2 block4 block4 block2 block3

41. • “/aaa.txt” open(new Path(“/aaa.txt”)) ( ) HDFS DistributedFileSystem NameNode block1 : DataNode1, DataNode3 block2 : DataNode3, DataNode4 aaa.txt : block1, block2. block3, block4 block1 : DataNode1, DataNode3 block2 : DataNode3, DataNode4 FSDataInputStream block3 : DataNode2, DataNode3 block4 : DataNode1, DataNode2 DateNode1 DateNode2 DateNode3 DateNode4 block1 block3 block1 block2 block4 block4 block2 block3

42. • “/aaa.txt” open(new Path(“/aaa.txt”)) ( ) HDFS DistributedFileSystem NameNode block1 : DataNode1, DataNode3 read() block2 : DataNode3, DataNode4 aaa.txt : block1, block2. block3, block4 block1 : DataNode1, DataNode3 block2 : DataNode3, DataNode4 FSDataInputStream block3 : DataNode2, DataNode3 block4 : DataNode1, DataNode2 DateNode1 DateNode2 DateNode3 DateNode4 block1 block3 block1 block2 block4 block4 block2 block3

46. • “/aaa.txt” open(new Path(“/aaa.txt”)) ( ) HDFS DistributedFileSystem NameNode block1 : DataNode1, DataNode3 read() block2 : DataNode3, DataNode4 aaa.txt : block1, block2. block3, block4 block1 : DataNode1, DataNode3 block2 : DataNode3, DataNode4 FSDataInputStream block3 : DataNode2, DataNode3 block3 : DataNode2, DataNode3 block4 : DataNode1, DataNode2 block4 : DataNode1, DataNode2 DateNode1 DateNode2 DateNode3 DateNode4 block1 block3 block1 block2 block4 block4 block2 block3

49. • “/aaa.txt” open(new Path(“/aaa.txt”)) ( ) HDFS DistributedFileSystem NameNode block1 : DataNode1, DataNode3 read() block2 : DataNode3, DataNode4 aaa.txt : block1, block2. block3, block4 close() block1 : DataNode1, DataNode3 block2 : DataNode3, DataNode4 FSDataInputStream block3 : DataNode2, DataNode3 block3 : DataNode2, DataNode3 block4 : DataNode1, DataNode2 block4 : DataNode1, DataNode2 DateNode1 DateNode2 DateNode3 DateNode4 block1 block3 block1 block2 block4 block4 block2 block3

60. • - - -

61. • - - 9.1.1 - (/d1/r1/n1, /d1/r1/n1) = 0 d1 d2 (/d1/r1/n1, /d1/r1/n2) = 2 (/d1/r1/n1, /d1/r2/n3) = 4 r1 r2 r3 (/d1/r1/n1, /d2/r3/n4) = 6 n1 n2 n3 n4

62. • HDFS DistributedFileSystem NameNode FSDataOutputStream DateNode1 DateNode2 DateNode3

63. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode FSDataOutputStream DateNode1 DateNode2 DateNode3

66. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream DateNode1 DateNode2 DateNode3

67. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream ack DateNode1 DateNode2 DateNode3

70. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream DataStreamer ack DateNode1 DateNode2 DateNode3

72. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream block1 : DataNode1, DataNode2, DataNode3 DataStreamer ack DateNode1 DateNode2 DateNode3

73. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream block1 : DataNode1, DataNode2, DataNode3 DataStreamer ack DateNode1 DateNode2 DateNode3

74. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream block1 : DataNode1, DataNode2, DataNode3 DataStreamer ack DateNode1 DateNode2 DateNode3 block1

75. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream block1 : DataNode1, DataNode2, DataNode3 DataStreamer ack DateNode1 DateNode2 DateNode3 block1 block1

76. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream block1 : DataNode1, DataNode2, DataNode3 DataStreamer ack DateNode1 DateNode2 DateNode3 block1 block1 block1

82. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() close() FSDataOutputStream block1 : DataNode1, DataNode2, DataNode3 DataStreamer ack DateNode1 DateNode2 DateNode3 block1 block1 block1

83. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() close() FSDataOutputStream block1 : DataNode1, DataNode2, DataNode3 DataStreamer ack DateNode1 DateNode2 DateNode3 block1 block1 block1

85. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream DataStreamer ack DateNode1 DateNode2 DateNode3 block1

86. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream DataStreamer ack DateNode1 DateNode2 DateNode3 block1 block1

89. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream DataStreamer ack DateNode1 DateNode2 DateNode3 block2 block1 block1

92. • create(new Path(“/aaa.txt”)) HDFS DistributedFileSystem NameNode write() FSDataOutputStream DataStreamer ack DateNode1 DateNode2 DateNode3 block2 block1 block1 block2

100. • - dfs.replication.min( 1) - (dfs.replication 3) -

101. • 1. ( ) 2. 3. 4. ( )

102. • - fs.create(new Path("p")); - OutputStream out = fs.create(new Path("p")); out.write("content".getBytes("UTF-8")); out.flush();

103. • - FSDataOutputStream sync() - sync() close() FSDataOutputStream out = fs.create(new Path("p")); out.write("content".getBytes("UTF-8")); out.flush(); out.sync();

104. • - ‣ sync() ‣ sync() ‣ sync()

105. distcp • 2 HDFS - hadoop distcp hdfs://namenode1/foo hdfs://namenode2/bar - hadoop distcp -overwrite hdfs://namenode1/foo hdfs://namenode2/bar/foo - hadoop distcp -update hdfs://namenode1/foo hdfs://namenode2/bar/foo • MapReduce - 256MB (1GB 4 ) - map ( ) - map 1 (tasktraker) 20map

106. Hadoop • • HAR • hadoop archive -archiveName ﬁles.har /my/ﬁles /my

107. Hadoop • - ( ) - - HAR MapReduce ( 7.2.1.4 CombineFileInputFormat )

108. • HDFS - - - - • distcp • HAR

109. • •

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